Always wanted to use our i3 (aka Sparky) as our outdoor adventure car. We considered a rear hitch, but we have bikes, skis, a cargo box, kayaks, and paddle board. So that means a roof rack. But, we needed to be mindful of the sunroof on our i3. So when SeaSucker had a 20% off sale on everything this spring, we took the plunge and purchased Monkey Bars for $420. We also wanted an universal rack solution to avoid having buy a (specific) rack for each current (and future) car. Here’s my install solution for mounting bike racks.
First, we decided to replace our 20 year old bike racks with frame mount racks instead of fork mounts. This is because 1) of modern thru axles and 2) to maximize storage in Sparky. We decided on BMW’s bike rack via Amazon. They’re made by Thule and are essentially their rebranded ProRide XT rack. Via Amazon they were $135 w/Prime (vs Thule’s ProRide XT for $230 @ REI). And, there're the newest version of the Thule, with a locking clamp and updated clamp shape.
https://www.amazon.com/BMW-82-71-2-166- ... %3D&sr=8-2
Next, the BMW rack are designed their T-track rack so I had to find a round bar mount solution. They're $20 a piece. These Thule square bar adapter worked perfectly:
https://www.amazon.com/dp/B0791RW7N8?re ... ZJEY3GXE0Y
Ok. Now the install. Normally, you want to have the rack mounted corners or edges of the roof. BUT, that’s not case case w/the i3 w/a sunroof. Unlike normal sunroofs, the i3 mounts it’s sunroof along the center track instead of along the outside edges. You can see the glass mounting points from the inside when you open the sunroof halfway. This means mounting the suction cups on the corners are actually furthest from the sunroof’s mounting structure, thus are at its weakest points and prone to excessive and worrisome up and down wobbling.
Position 1: Another person on another thread had their Monkey Bars customized with smaller 4.5” suctions. This allows half of the front suctions to sit on the metal sheet between the windshield and the sunroof. Great idea. However, instead of custom ordering the change, I simply purchased the standard monkey bars on sale and then 2x 4.5” replacement suction cups and caps for $22 (on sale). This brought the mokey bars to $450, vs. $600+ if you custom order them through Seasucker.
Postion 2: Building on the idea above, if you opt to stick with the original 6” suckers you can instead mount the front bars at the rear of the sunroof, with one suction on the sunroof and the other on the rear metal roof panel. I also positioned the towers about 3-4 inches away from the sunroof glass mounts/tracks. This allowed an adequate spread between the two towers, not too much distance from the glass' mount/pivot points, and provided roughly equal distance from the outside edge to tower, between the towers, and to the other outside edge. Also, it’s important to mount the rear suction as close to the edge at possible. This will minimize flexing from the metal when under weight. The sheet metal is really really thin. Lastly, the disadvantage of this position is the rear bar is no longer level to the front bar and is now about 2-3 inches lower. For cargo boxes and water crafts, it will angle the bulk of the mass upwards and will cause air lift problems when at speed. For bike racks, it won't matter much. But, this may cause the rear hatch to not fully open if your bike rack is too long.
Finally, I got a Yakima cable lock to secure the rack to the car. The bike rack itself are lockable to the monkey bars.
https://www.amazon.com/Yakima-Trunk-Mou ... 3426&psc=1
Hope this helps. I'll post an update when the 4.5" suction cups arrives.
https://drive.google.com/drive/folders/ ... sp=sharing